搜索结果: 'gmp t cell activator'

Mucosal Langerhans cells (LCs) originate from pre-dendritic cells and monocytes. However,the mechanisms involved in their in situ development remain unclear. Here,we demonstrate that the differentiation of murine mucosal LCs is a two-step process. In the lamina propria,signaling via BMP7-ALK3 promotes translocation of LC precursors to the epithelium. Within the epithelium,TGF-β1 finalizes LC differentiation,and ALK5 is crucial to this process. Moreover,the local microbiota has a major impact on the development of mucosal LCs,whereas LCs in turn maintain mucosal homeostasis and prevent tissue destruction. These results reveal the differential and sequential role of TGF-β1 and BMP7 in LC differentiation and highlight the intimate interplay of LCs with the microbiota. View Publication

1,25-Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) can modulate immune responses,but whether it directly affects B cell function is unknown. Patients with systemic lupus erythematosus,especially those with antinuclear Abs and increased disease activity,had decreased 1,25(OH)(2)D(3) levels,suggesting that vitamin D might play a role in regulating autoantibody production. To address this,we examined the effects of 1,25(OH)(2)D(3) on B cell responses and found that it inhibited the ongoing proliferation of activated B cells and induced their apoptosis,whereas initial cell division was unimpeded. The generation of plasma cells and postswitch memory B cells was significantly inhibited by 1,25(OH)(2)D(3),although the up-regulation of genetic programs involved in B cell differentiation was only modestly affected. B cells expressed mRNAs for proteins involved in vitamin D activity,including 1 alpha-hydroxylase,24-hydroxylase,and the vitamin D receptor,each of which was regulated by 1,25(OH)(2)D(3) and/or activation. Importantly,1,25(OH)(2)D(3) up-regulated the expression of p27,but not of p18 and p21,which may be important in regulating the proliferation of activated B cells and their subsequent differentiation. These results indicate that 1,25(OH)(2)D(3) may play an important role in the maintenance of B cell homeostasis and that the correction of vitamin D deficiency may be useful in the treatment of B cell-mediated autoimmune disorders. View Publication

Biologic TNFα inhibitors are a mainstay treatment option for patients with rheumatoid arthritis (RA) refractory to other treatment options. However,many patients either do not respond or relapse after initially responding to these agents. This study was carried out to identify biomarkers that can distinguish responder from non-responder patients before the initiation of treatment. The level of cytokines in plasma and those produced by ex vivo T cells,B cells and monocytes in 97 RA patients treated with biologic TNFα inhibitors was measured before treatment and after 1 and 3 months of treatment by multiplex analyses. The frequency of T cell subsets and intracellular cytokines were determined by flow cytometry. The results reveal that pre-treatment,T cells from patients who went on to respond to treatment with biologic anti-TNFα agents produced significantly more GM-CSF than non-responder patients. Furthermore,immune cells from responder patients produced higher levels of IL-1β,TNFα and IL-6. Cytokine profiling in the blood of patients confirmed the association between high levels of GM-CSF and responsiveness to biologic anti-TNFα agents. Thus,high blood levels of GM-CSF pre-treatment had a positive predictive value of 87.5% (61.6 to 98.5% at 95% CI) in treated RA patients. The study also shows that cells from most anti-TNFα responder patients in the current cohort produced higher levels of GM-CSF and TNFα pre-treatment than non-responder patients. Findings from the current study and our previous observations that non-responsiveness to anti-TNFα is associated with high IL-17 levels suggest that the disease in responder and non-responder RA patients is likely to be driven/sustained by different inflammatory pathways. The use of biomarker signatures of distinct pro-inflammatory pathways could lead to evidence-based prescription of the most appropriate biological therapies for different RA patients. View Publication

Most polyreactive and antinuclear antibodies are removed from the human antibody repertoire during B cell development. To elucidate how B cell receptor (BCR) signaling may regulate human B cell tolerance,we tested the specificity of recombinant antibodies from single peripheral B cells isolated from patients suffering from X-linked agammaglobulinemia (XLA). These patients carry mutations in the Bruton's tyrosine kinase (BTK) gene that encode an essential BCR signaling component. We find that in the absence of Btk,peripheral B cells show a distinct antibody repertoire consistent with extensive secondary V(D)J recombination. Nevertheless,XLA B cells are enriched in autoreactive clones. Our results demonstrate that Btk is essential in regulating thresholds for human B cell tolerance. View Publication

BAFF plays a central role in B-lineage cell biology; however,the regulation of BAFF-binding receptor (BBR) expression during B cell activation and differentiation is not completely understood. In this study,we provide a comprehensive ex vivo analysis of BBRs in human B-lineage cells at various stages of maturation,as well as describe the events that drive and regulate receptor expression. Our data reveal that B-lineage cells ranging from naive to plasma cells (PCs),excluding bone marrow PCs,express BAFF-R uniformly. In contrast,only tonsillar memory B cells (MB) and PCs,from both tonsil and bone marrow tissues,express BCMA. Furthermore,we show that TACI is expressed by MB cells and PCs,as well as a subpopulation of activated CD27(neg) B cells. In this regard,we demonstrate that TACI is inducible early upon B cell activation and this is independent of B cell turnover. In addition,we found that TACI expression requires activation of the ERK1/2 pathway,since its expression was blocked by ERK1/2-specific inhibitors. Expression of BAFF-R and B cell maturation Ag (BCMA) is also highly regulated and we demonstrate that BCMA expression is only acquired in MB cells and in a manner accompanied by loss of BAFF-R expression. This inverse expression coincides with MB cell differentiation into Ig-secreting cells (ISC),since blocking differentiation inhibited both induction of BCMA expression and loss of BAFF-R. Collectively,our data suggest that the BBR profile may serve as a footprint of the activation history and stage of differentiation of normal human B cells. View Publication

Ab-targeted vaccination involves targeting a receptor of choice expressed by dendritic cells (DCs) with Ag-coupled Abs. Currently,there is little consensus as to which criteria determine receptor selection to ensure superior Ag presentation and immunity. In this study,we investigated parameters of DC receptor internalization and determined how they impact Ag presentation outcomes. First,using mixed bone marrow chimeras,we established that Ag-targeted,but not nontargeted,DCs are responsible for Ag presentation in settings of Ab-targeted vaccination in vivo. Next,we analyzed parameters of DEC205 (CD205),Clec9A,CD11c,CD11b,and CD40 endocytosis and obtained quantitative measurements of internalization speed,surface turnover,and delivered Ag load. Exploiting these parameters in MHC class I (MHC I) and MHC class II (MHC II) Ag presentation assays,we showed that receptor expression level,proportion of surface turnover,or speed of receptor internalization did not impact MHC I or MHC II Ag presentation efficiency. Furthermore,the Ag load delivered to DCs did not correlate with the efficiency of MHC I or MHC II Ag presentation. In contrast,targeting Ag to CD8(+) or CD8(-) DCs enhanced MHC I or MHC II Ag presentation,respectively. Therefore,receptor expression levels,speed of internalization,and/or the amount of Ag delivered can be excluded as major determinants that dictate Ag presentation efficiency in setting of Ab-targeted vaccination. View Publication

Granzyme B (grB) is a serine proteinase released by cytotoxic lymphocytes (CLs) to kill abnormal cells. GrB-mediated apoptotic pathways are conserved in nucleated cells; hence,CLs require mechanisms to protect against ectopic or misdirected grB. The nucleocytoplasmic serpin,proteinase inhibitor 9 (PI-9),is a potent inhibitor of grB that protects cells from grB-mediated apoptosis in model systems. Here we show that PI-9 is present in CD4(+) cells,CD8(+) T cells,NK cells,and at lower levels in B cells and myeloid cells. PI-9 is up-regulated in response to grB production and degranulation,and associates with grB-containing granules in activated CTLs and NK cells. Intracellular complexes of PI-9 and grB are evident in NK cells,and overexpression of PI-9 enhances CTL potency,suggesting that cytoplasmic grB,which may threaten CL viability,is rapidly inactivated by PI-9. Because dendritic cells (DCs) acquire characteristics similar to those of target cells to activate naive CD8(+) T cells and therefore may also require protection against grB,we investigated the expression of PI-9 in DCs. PI-9 is evident in thymic DCs (CD3(-),CD4(+),CD8(-),CD45(+)),tonsillar DCs,and DC subsets purified from peripheral blood (CD16(+) monocytes and CD123(+) plasmacytoid DCs). Furthermore,PI-9 is expressed in monocyte-derived DCs and is up-regulated upon TNF-alpha-induced maturation of monocyte-derived DCs. In conclusion,the presence and subcellular localization of PI-9 in leukocytes and DCs are consistent with a protective role against ectopic or misdirected grB during an immune response. View Publication

Mobile sensing based on the integration of microfluidic device and smartphone,so-called MS2 technology,has enabled many applications over recent years,and continues to stimulate growing interest in both research communities and industries. In particular,it has been envisioned that MS2 technology can be developed for various cell functional assays to enable basic research and clinical applications. Toward this direction,in this paper,we describe the development of a MS2-based cell functional assay for testing cell migration (the Mkit). The system is constructed as an integrated test kit,which includes microfluidic chips,a smartphone-based imaging platform,the phone apps for image capturing and data analysis,and a set of reagent and accessories for performing the cell migration assay. We demonstrated that the Mkit can effectively measure purified neutrophil and cancer cell chemotaxis. Furthermore,neutrophil chemotaxis can be tested from a drop of whole blood using the Mkit with red blood cell (RBC) lysis. The effects of chemoattractant dose and gradient profile on neutrophil chemotaxis were also tested using the Mkit. In addition to research applications,we demonstrated the effective use of the Mkit for on-site test at the hospital and for testing clinical samples from chronic obstructive pulmonary disease patient. Thus,this developed Mkit provides an easy and integrated experimental platform for cell migration related research and potential medical diagnostic applications. View Publication